a) Field of the Invention
This invention relates to a resectoscope of the kind having an outer barrel and also an inner barrel formed as an insulating element at its distal end, to have passed through it a telescope and a means of supplying current to the distal resection loop, which means is displaceable by a carrier, the space left open in the inner barrel being used to feed an irrigating liquid into the bladder and the space between the inner and outer barrels being used to drain out the irrigating liquid through distal openings in the outer barrel.
b) Description of the Prior Art
Such resectoscopes are disclosed in DE-GM 7426959 U.S. Pat. No. 4,132,227, DE-GM 7626244 and DE-OS-2617556. To achieve an adequate circulation of irrigating liquid, these known resectoscopes have barrels of large cross-section, particularly at the distal end, which makes them more difficult to insert into the urethra and may even result in injury being caused to the mucous membrane of the urethra.
The main object of the present invention is, in resectoscopes of the above-mentioned kind, to provide a strong insulating element at the distal end of the inner barrel which will prevent current from being transmitted from the resection loop to the outer barrel, whilst at the same time providing adequate drainage for irrigant media from the bladder with the smallest possible cross-section for the outer barrel.
To this end, the present invention consists in a resectoscope having an outer barrel and having an inner barrel, formed as an insulating element at its distal end, to have passed through it a telescope and a means of supplying current to the distal resection loop, which means is displaceable by a carrier, the space left open in the inner barrel being used to feed an irrigating liquid into the bladder and the space between the inner and outer barrels being used to drain out the irrigating liquid through distal openings in the outer barrel, characterised in that the distal insulating element of the inner barrel is reduced in a diameter at the outer circumference in a part-cylindrical configuration providing a circumferential recess, over a length for which it is overlapped by the distal end of the outer barrel to form a space which is connected to slots for the outflow of irrigating liquid and to a closable connecting nozzle.
By achieving the object in this way, it is possible to insulate the resection loop satisfactorily from the barrel and the user of the resectoscope whilst making the distal end of the instrument strong enough for insertion in the urethra, and to obtain a sufficiently large space between the inner and outer barrels to allow the liquid to be drained out of the bladder even though the insulating element is strongly made.
The circumferential recess in the insulating element makes the space between the inner and outer barrels available and at the same time it keeps the cross-section of the resectoscope relatively small at the distal end.
In a preferred embodiment of the invention the proximal end of the insulating element whose diameter is reduced to that of the inner barrel is non-releasably connected to the distal end of the inner barrel by means of a cylindrical ring.
Advantageously, the insulating element has a cylindrical recess to receive the inner barrel.